#include "grader.h"
#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define fir first
#define sec second
#define vec vector
#define arr array
const int N = 6e2 + 5;
int n;
arr<vec<int>, N> adj;
int nm_ids;
arr<int, N> id;
void dfs(int u = 1) {
id[u] = ++nm_ids;
for (int v : adj[u])
if (!id[v]) dfs(v);
}
bool chck(int i) {
vec<int> qry;
for (int j = 1; j <= i; j++) qry.push_back(id[j]);
return query(qry);
}
int srch() {
int lw = 1, hg = n;
while (lw != hg) {
int md = (lw + hg) / 2;
if (chck(md)) hg = md;
else lw = md + 1;
}
for (int u = 1; u <= n; u++)
if (id[u] == lw) return u;
assert(false); return -1;
}
void intl() {
nm_ids = 0;
for (int u = 1; u <= n; u++) {
adj[u].clear();
id[u] = 0;
}
}
int findEgg (int _n, vec<pii> _e) {
intl();
n = _n;
for (pii x : _e)
adj[x.fir].push_back(x.sec), adj[x.sec].push_back(x.fir);
dfs();
int ans = srch();
return ans;
}
